System performance and functional analysis for the methanogenic bioreactor of a two-phase anaerobic digestion system: The effect of influent sulfate. (20th September 2022)

• Record Type: Journal Article
• Authors: Li, Jun; Li, Aimin; Li, Yan; Cai, Minhui; Wang, Duanhao; Tian, Yechao; Wu, Ji; Wang, Zheng; Xing, Liqun; Zhang, Quanxing
• Is Part Of: Journal of cleaner production. Volume 367(2022)
• Publication Date: 2022-09-20
• Subjects: Methanogenic reactor -- High sulfate -- Functional analysis -- Methanogenesis pathway -- PICRUSt2; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2022.132829
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: In this study, a lab-scale bioreactor was built to investigate the influence of sulfate on the overall performance, microbial community, and metabolic pathways in the methanogenic bioreactor of a two-phase anaerobic digestion system. The results demonstrated that by gradually cultivating the sludge of the methanogenic bioreactor, a chemical oxygen demand (COD) degradation efficiency of over 65% was achieved for sulfate contents from 10, 000 mg/L to 30, 000 mg/L. The sulfate reduction performance could only be maintained at a high level for influent COD/sulfate ratios no less than 1.88. In addition, the methane production rate (MPR) decreased from 0.92 L/L/d to 0.28 L/L/d, and the proportion of methane in biogas dropped from 51% to 33% when the influent sulfate exceeded 30, 000 mg/L. High-throughput sequencing coupled with PICRUSt2 revealed that the dissimilatory sulfate process could be enhanced by sulfate within 30, 000 mg/L. While an amount of greater than 5000 mg/L sulfate remarkably inhibited the assimilatory sulfate reduction process, and this inhibition was induced by the down-regulation of the cys NC, cys C, cys I and cys J genes. For the methanogenic process, sulfate contents within 30, 000 mg/L had no obvious impact on all of the acetoclastic, hydrogenotrophic, and methylotrophic methanogenesis processes, but serious suppression was observed for sulfate amounts greater than 30, 000 mg/L. This inhibition primarily originated from the decrease in mcr A, mcr B, and mcr G genes that regulate the conversion of methylcoenzyme M to methane, the last step of all three methanogenesis pathways. Graphical abstract: Image 1 Highlights: COD degradation efficiency of over 65% was achieved for sulfate contents over 10, 000 mg/L. High sulfate reduction performance was achieved for COD/sulfate ratio over 1.88. Sulfate content within 30, 000 mg/L favored dissimilatory sulfate reduction pathway. Sulfate inhibition to methanogenesis process caused by the decrease of Mcr ABG genes.